The magneto-optical recording and reproducing apparatuses adopting the magnetic field modulation perform recording and reproducing information in the following way. In recording information, while projecting a laser beam, an external magnetic field is applied onto a magnetic film of a magneto-optical disk, and information is recorded by modulating the external magnetic field. In reproducing information, a laser beam is projected onto the magnetic film of the magneto-optical disk, and the information is reproduced by detecting the light reflected therefrom. Therefore, how fast the information can be recorded is determined by the speed in reversing the magnetic field of the magnetic film. For this reason, the magneto-optical recording and reproducing apparatus adopting the magnetic field modulation requires a magnetic head device designed for magneto-optical disks including a compact magnetic head separately provided for magnetic field modulation.
In the conventional magneto-optical recording and reproducing apparatuses, for example, a fixed type of magnetic head device designed for magneto-optical disks shown in FIGS. 16 and 17 has been employed, and the configuration thereof will be described below.
FIG. 16 is a view showing a schematic configuration of a magneto-optical recording and reproducing apparatus employing a fixed-type magnetic head device. FIG. 17 is an enlarged view showing essential parts of the magnetic head device.
As shown in the figures, a magneto-optical disk (hereinafter simply referred to as a disk) 101 includes a transparent plate 101a, a magnetic film 101b, and a protective film 101c. An optical pickup 102 is provided for recording information by projecting a laser beam onto the disk 101 and for reproducing the information by projecting a laser beam onto the disk 101 and detecting the light reflected therefrom. A magnetic head 103 includes a magnetic substance having a coil 103a wound around the circumference thereof. A turn table 104 for rotating the disk 101 is directly connected to a spindle motor. A connecting member 105 connects the optical pickup 102 and the magnetic head 103 which are placed so as to face one another having the optical disk 101 in between. The optical pickup 102 and the magnetic head 103 are interlocked by the connecting member 105 when they are moved in a radial direction of the disk 101.
According to the above arrangement, in recording information, by projecting a strong laser beam from the optical pickup 102 onto the rotating disk 101, the temperature of the magnetic film 101b raises above its Curie temperature, and a magnetic field corresponding to a recording signal is applied from the magnetic head 103 onto the magnetic film 101b. As a result, the magnetization of the magnetic film 101b is arranged in a predetermined direction, thereby recording information. In reproducing information, a weak laser beam is projected from the optical pickup 102 onto the disk 101, and the optical pickup 102 detects the light reflected from the disk 101, thereby reproducing the information.
In the described fixed type magnetic head device, when the disk 101 vibrates as it rotates, it may hit the magnetic head 103. In order to avoid this, a space .delta..sub.10 of substantially 0.5-1.0 mm is required between the disk 101 and the magnetic head 103. For this reason, the coil 103a is required to be made larger in order to generate a sufficient magnetic field for recording onto the magnetic film 101b of the disk 101. However, if the coil 103a is made larger, the magnetic head 103 also becomes larger in size. Furthermore, the speed in reversing the magnetic field is reduced, and the above problem is a serious drawback in high speed and high density recording.
In order to counteract this problem, a floating type magnetic head device shown in FIGS. 18 and 19 has been conventionally proposed. The floating type magnetic head device includes a magnetic head 103, a slider 106 integrally provided with the magnetic head 103, and a support arm 107 composed of a spring for supporting the magnetic head 103 and the slider 106. In this arrangement, the magnetic head 103 is floated as the slider 106 receives an air flow generated when the disk 101 rotates at high speed. Further, a space .delta..sub.11 of several .mu.m multiplied by ten is maintained between the disk 101 and the magnetic head 103.
The above arrangement of the magnetic head device permits a reduction in the distance between the magnetic head 103 and the magnetic film 101b of the disk 101. As a result, the coil 103a of the magnetic head 103 can be made smaller, thereby enabling a higher speed and a higher density recording.
In the magneto-optical recording and reproducing apparatus wherein the disk 101 is being rotated at high speed, a sufficient floating force is exerted toward the floating type magnetic head device. However, in the magneto-optical recording and reproducing apparatus wherein the disk 101 is being rotated at relatively low speed, a sufficient floating force is not exerted. Therefore, the floating type magnetic head can be used only in the magneto-optical recording and reproducing apparatus wherein the disk 101 is being rotated at high speed.
Moreover, even when a sufficient floating force is exerted toward the floating type magnetic head device, a compact coil is required for the high speed and high density recording. Thus, the space between the magnetic head 103 and the disk 101 needs to be set extremely small. However, as the space between the magnetic head 103 and the disk 101 is made smaller, the possibility for the disk 101 hitting the magnetic head 103 increases when the disk 101 vibrates.